Biochemistry of the retina, illustration. The retina is the light-sensitive layer lining the rear of the interior of the eyeball. Its microscopic structure is shown here, with cells known as rods and cones. These include a bilayer membrane that contains the light-sensitive receptor protein rhodopsin. The bilayer component of the membrane consists of chemicals called phospholipids (blue). Labelled here is the long-chain polyunsaturated fatty acid (LCP) component of the phospholipids. LCPs play a key role as a dietary source of chemicals for retinal development.